Active Beam Expander with Positioning Gimbal

Active Beam Expander with Positioning Gimbal :

This project required delivery of a High Energy Laser Testbed Optical Telescope with a three-axis gimbal positioning system. This system includes a 12-inch (30-cm) on-axis telescope with a electromechanically focused secondary mirror and a Magneto-Hydrodynamic Inertial Reference Unit (MIRU) that produces a reference laser beam for feedback into a pointing stabilization system. The secondary mirror is moved for focus using a custom flexure mechanism optimized for high lateral stiffness and smooth motion.

The Positioning Gimbal is designed to point the telescope and acquisition sensor package in elevation and azimuth and provide a platform for testing and evaluation of beam control. When combined, these systems provide an extremely capable means of focusing a high energy laser beam down range.

During development, WMD was required to constantly balance the high performance nature of this project with the limitations of manufacturing a complicated and potentially dangerous product. Working with high-intensity lasers, potentially greater than 10 kw, required designers to incorporate extra layers of control and safety.

Challenges:

The original design called for moving the primary mirror for focus adjustment. Once this design was implemented it proved to be problematic, so the primary focusing system was re-designed to be a much simpler manual system. With the manual system, the primary can be focused and then locked in place, thereby eliminating the need to re-adjust the mirror. All other necessary focusing can be achieved by the secondary mirror focusing mechanism mentioned above.